text: /**
   * \addtogroup rimeipolite
   * @{
   */
  
  /*
   * Copyright (c) 2007, Swedish Institute of Computer Science.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of the Institute nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * This file is part of the Contiki operating system.
   *
   * $Id: ipolite.c,v 1.17 2010/02/23 18:38:05 adamdunkels Exp $
   */
  
  /**
   * \file
   *         Ipolite Anonymous best effort local area BroadCast (ipolite)
   * \author
   *         Adam Dunkels <adam@sics.se>
   */
  
  #include "net/rime.h"
  #include "net/rime/ipolite.h"
  #include "lib/random.h"
  
  #include <string.h>
  
  #ifndef MAX
  #define MAX(a, b) ((a) > (b)? (a) : (b))
  #endif /* MAX */
  
  #ifndef MIN
  #define MIN(a, b) ((a) < (b)? (a) : (b))
  #endif /* MIN */
  
  #define DEBUG 0
  #if DEBUG
  #include <stdio.h>
  #define PRINTF(...) printf(__VA_ARGS__)
  #else
  #define PRINTF(...)
  #endif
  
  /*---------------------------------------------------------------------------*/
  static void
  recv(struct broadcast_conn *broadcast, const rimeaddr_t *from)
  {
    struct ipolite_conn *c = (struct ipolite_conn *)broadcast;
    if(c->q != NULL &&
       packetbuf_datalen() == queuebuf_datalen(c->q) &&
       memcmp(packetbuf_dataptr(), queuebuf_dataptr(c->q),
  	    MIN(c->hdrsize, packetbuf_datalen())) == 0) {
      /* We received a copy of our own packet, so we increase the
         duplicate counter. If it reaches its maximum, do not send out
         our packet. */
      c->dups++;
      if(c->dups == c->maxdups) {
        queuebuf_free(c->q);
        c->q = NULL;
        ctimer_stop(&c->t);
        if(c->cb->dropped) {
          c->cb->dropped(c);
        }
      }
    }
    if(c->cb->recv) {
      c->cb->recv(c, from);
    }
  }
  /*---------------------------------------------------------------------------*/
  static void
  sent(struct broadcast_conn *bc, int status, int num_tx)
  {
  
  }
  /*---------------------------------------------------------------------------*/
  static void
  send(void *ptr)
  {
    struct ipolite_conn *c = ptr;
    
    PRINTF("%d.%d: ipolite: send queuebuf %p\n",
  	 rimeaddr_node_addr.u8[0],rimeaddr_node_addr.u8[1],
  	 c->q);
    
    if(c->q != NULL) {
      queuebuf_to_packetbuf(c->q);
      queuebuf_free(c->q);
      c->q = NULL;
      broadcast_send(&c->c);
      if(c->cb->sent) {
        c->cb->sent(c);
      }
    }
  }
  /*---------------------------------------------------------------------------*/
  static const struct broadcast_callbacks broadcast = { recv, sent };
  /*---------------------------------------------------------------------------*/
  void
  ipolite_open(struct ipolite_conn *c, uint16_t channel, uint8_t dups,
  	  const struct ipolite_callbacks *cb)
  {
    broadcast_open(&c->c, channel, &broadcast);
    c->cb = cb;
    c->maxdups = dups;
    PRINTF("ipolite open channel %d\n", channel);
  }
  /*---------------------------------------------------------------------------*/
  void
  ipolite_close(struct ipolite_conn *c)
  {
    broadcast_close(&c->c);
    ctimer_stop(&c->t);
    if(c->q != NULL) {
      queuebuf_free(c->q);
      c->q = NULL;
    }
  }
  /*---------------------------------------------------------------------------*/
  int
  ipolite_send(struct ipolite_conn *c, clock_time_t interval, uint8_t hdrsize)
  {
    if(c->q != NULL) {
      /* If we are already about to send a packet, we cancel the old one. */
      PRINTF("%d.%d: ipolite_send: cancel old send\n",
  	   rimeaddr_node_addr.u8[0],rimeaddr_node_addr.u8[1]);
      queuebuf_free(c->q);
    }
    c->dups = 0;
    c->hdrsize = hdrsize;
    if(interval == 0) {
      PRINTF("%d.%d: ipolite_send: interval 0\n",
  	   rimeaddr_node_addr.u8[0],rimeaddr_node_addr.u8[1]);
      if(broadcast_send(&c->c)) {
        if(c->cb->sent) {
  	c->cb->sent(c);
        }
        return 1;
      }
  
    } else {
      c->q = queuebuf_new_from_packetbuf();
      if(c->q != NULL) {
        ctimer_set(&c->t,
  		 interval / 2 + (random_rand() % (interval / 2)),
  		 send, c);
        return 1;
      }
      PRINTF("%d.%d: ipolite_send: could not allocate queue buffer\n",
  	   rimeaddr_node_addr.u8[0],rimeaddr_node_addr.u8[1]);
    }
    return 0;
  }
  /*---------------------------------------------------------------------------*/
  void
  ipolite_cancel(struct ipolite_conn *c)
  {
    ctimer_stop(&c->t);
    if(c->q != NULL) {
      queuebuf_free(c->q);
      c->q = NULL;
    }
  }
  /*---------------------------------------------------------------------------*/
  /** @} */
  